Improvement in let-off mechanism for looms



Devin M. coLLiN'S, or LoWELL, MASSACHUSETTS.

Letters Patent No. 95,197, `dated September, 28, lSt/Q.-

l IMPRQVMENT 1N LET-orr- MECH'ANISM Fon Looms.`

x The Schedule referred to in these Lettexs Patent and making part o the same.

To all whom it may concern Be it known that I, DAVID M. GoLLiNs, of Lowell, inthe county of-Middlesex, and` State of Massachusetts, have invented certain new and useful Improvements in `Looms `for Weaving, ofwhich the following l i is a full, clear`,pandI exact description, reference being had to the accompanying drawings, making part of this specilicatiomiu which` y Figure l represents an end elevationl of a portion of an ordinary loom having `Iny improvements 'applied thereto.

n l Figure 2 is a rear-side, and l l Figure 3, a top view of one end of' the loom. Figure 41s a transverse section onthe line a b of figs. 2 and 3. The circles `3 and` 4 only indicate diameters of the full beam, and of the gear M. Figures 5 and Gare opposite transverse sections of smallerportions of the loom, theV former on theline j, and the latter n theliue yc d. f

Figures 7 is a `cross-section of `the tension-bar, in size. and forur substantially my impr0vem'ent.`

`This invention `relates Vto that part of a loom which is known as the/letoff motion orregulator, or feed, and has for itsV object, the regular and uniform delivery of warp from the yarnvbcam during the entire process of `weaving all the warp contained on such beam,` and of preserving `the same even tension on the warp, whether the beam is full,or partly full, or nearly empty.

This invention consists- Y First, in the tension-bar A,`.of peculiar form or construction, asshown, and having combined therewith an adjustable arm, B, which controls theaction of the' pawl C ou the ratchet-wheel l), by means of the action, draught, or tension of the yaru`on.the outer and overhanging cam-shaped edge, `lil, which forms one kind of progressive lever.

Second, my invention consists in the combination, with the tension-bar and arui, as shown and described, and with the beam-gear M, of the cam-lever F, pawl 5G, ratchet-wheel D, gears `I and K, worm" L,` and a friction-device, allarrauged as `hereinafter described, and operating in connection with the part-s first named.

In the construction,application, and use of my said improvements, 'the peculiar form of the tension-bar,

.andxof the curved edge E, should be substantially preserved, maintained,,or imitated, in order to produce .the best and most desirable efect or result from its use, when applied to the loom inl connection Withthe elements or devices which make it operative, or with other devices or elements substantially the saine.A

i In the drawings I have shown the yarn-beam G and H, the former letter representing a full beam, and the latter ,an` empty one.

Red lines J showthedirection `of the warp from the yard-beam to and over the tension-bar and forward to the breast-beam N, except in 7, where diverging lilies J show the different direction of the Warp from a beam having different quantities of yarn thereon, and the bearing,action, or eiiect of such warp upon the portion E of the tension-bar to draw it gradually downward as the yarn is woven ofi,- from the beam. i

This` gradual downward,movement of the edge E of the tension-bar carries the lower end, e, of the arin B away. from the pivcted head` of the pawl, or gradually increases the distance between the two last-nan1ed parts as the beam of yarn grows smaller, and allows the pawl to recede a greater distance, and thereby to `pass more frequently over and off from one or more teeth in tbe ratchet-wheel, so that when the pawl is carried back it turns the ratchet and the yarn=beam a greater part of `a revolution, and more rapidly the yarn un winds from the beam. When the yarn-beam is full, as when yfirst put into `the hmm, the uuwiuding action of said beam is necessarily very slow, as one entire revolution of a full beam will let oli' nearly or quite double the length of warp or yarn `of two revolutions of a beam ywhich is nearly empty, and this gradual let-olf, or unwinding action, or feed, is regulated by the adjustable arin B, and the tension-bar, `and by the tension of the warp or yarn,`

arm a sudicient distance from the pivoted head of thepawl to allow it v to pass one or more teeth on the ratchet toturu the same andthe yarn-beam, and allow the yarn to slacken and unwind.,

Alternate actions 0r operations, substantially the same, and gradually increasing in number and extent, are keptlup during the entire process of .weaving oli' a beam of yarn, and the same even and uniform .teusion of the warp is preserved, whether the yarn-beam is full, partly full, or nearly empty, the curved portion E of the tension-b ar acting as a progressive lever, increasing i'ts leverage as the yarn uuwinds from the beam, and as the beam of yarn grows smaller, said yarn yleading or lapping downward ou itsouter surface, and gradually, further from the centre of the bar, which, by the peculiar form of,the lever-portion E and by the adjustable arm, produces the desired effect, as hereinbefore described.

Any slight modification in the form of the portion E of the tension-bar, or changing t.to the curved form, shown in igs. l-and 4, will not prevent the successful working of the let-oft" motion, and such modifications I consider mere colorable alterations which I have contemplated. The form substantially shown in fig.7, I consider the best, when the adjusting-arm B is combined, as shown and described.

In connection with the tension-.bar and 'the arm B, as before described, I employ a cam-lever, F, which is pivoted to a stand, a, secured to the frame.

This lever F has an arm, b, to the top end of which I pivot the head of the pawl. A cam, It, on the shaft S, actuates the lever F, and the pawl, to turn the ratchet-wheel D, arrranged on a short shaft, T, supported in a box or bearing, U, secured to the frame. 0n the face of the ratchet-wheel is a bevel or other suitable` gear, K, which gears into a proper gear, I, on a cross-shaft, d, which also carries aworm, L, and this worm engages with the gear M on the end of the yarnbeam, the worm-shaft being supported by a stand or stands, W, projecting. inward, and fastened to the end of the loom.

On the outer end of the-shaft T is a disk, or a wheel, f, between which and the end of the bearing U, is a spiral spring, ,9. The former is for turning the shaft T backward or forward, by hand, to te'mpbrarily slacken or to tighten the warp, or to adj ust the beam and bring the proper tension on the warp after it has been slackened, and the latter is to produce friction on the shaft, and prevent it being turned backward by the backward actiou'of the pawl, or by accident otherwise.

Au adjustable collar, h, connected by one -or more set-screws, i, is arranged on the shaft T, to keep the gear K into acting contact with the gear I, and to iusure the compression of the spring f, thus forming a friction-device. The spring is concealed in a .cavity formed in the end of the bearing U.

The ratchet-wheel may be so constructed as to be turned more than one tooth at each forward and backward motion of the pawl, if preferred.

At the opposite end of the loom, and as shown in figs. 2 and 5, aat spring, k, is applied to the shaft of the tension-bar. The lower end of this spring bears against an adjustable stop or bracket, l, which may be set to accommodate the stiffness of the spring. This spring holds the tension-bar in position against the weight of the projecting portion E, and the tension, of the warp, and restores said bar to its proper set position after each beat of the lay, and thereby retains the arm B in its adj usted position, and prevents the frequent engagement. of the pawl with the ratchet, and measurably controls the action and insures (in connection with the arm B and the tension-bar) the successful operation of the other parts of the feed or let-olf, and the regular and uniform delivery of warp from the yarn-beam.

` When the loom is in motion, the rotating cam R keeps the lever F and the pawl in reciprocating motion on the toothed edge of the ratchet-wheel, occasionally or frequently moving backward (by the rising ofthe end e of the arm B, caused by the action of the tension of the warp on the progressive-lever edge E of the tension-bar) far enough to catch a tooth or teeth of the ratcl1et-wheel,and turning the latter and the yarn-beam to let off the necessary quantity or length of warp therefrom, proportionate to the fulness of the beam or the amount of warp thereon, and to the velocity or speed of tbe operating-loom.

lo slacken the warp for any purpose, I turn the beam back, by turning the' disk or wheel f, and to tighten the slackened warp, I lift the pawl and turn the wheel f in the opposite direction.

Having described vm y invention,

What Iclaim, and desire to secure by Letters Patent, is

1. The tension-bar A, in combination with the adjustable arm B, and spring k, all constructed, arranged, and operating in the manner and for the purpose specified.

2.`In combination, with the tension-bar A, arm B, spring lc, and the beam-gear M, as described, the camlever F, pawl C, ratchet-wheel D, gears I and K,'

worm L, earn R, and the friction-device, all arranged and operating in the manner and for the purpose set forth.

3. rlhe method, substantially as described, of controlling or regulating the action of the pawl C on the 1atcl1 .twl1eelD, to operate the let-off, for the uniform delivery of warp from the yarn-beam, b means of the adjustable arm -B and the tension-bar A, constructed and arranged as shown and described, and acted on by the unwinding warp, which gradually draws the portion E downward, and as gradually carries the end e of the arm away from the pivoted head of the pawl, or widens the distance between the two last-named parts, and increases the action of the latter proportionate to the amount of warp outhe beam.

DAVID M. COLLINS.

\Vitnesses:

J oHN E. CRANE, J. S. WHITNEY. 

